The object of the invention are improvements applicable to vertical mote moulding machines, that is, machines in which the motes are produced and exit the moulding chamber in a vertical position, in which position they arrive at the casting station.
These improvements allow an efficient moulding of holes, whether round or with other geometries, in which depth is greater than the cross section without requiring the use of cores. Thus the mote may be directly produced with the required conical or otherwise shaped protrusions, perfectly compacted and without said protrusions being deteriorated or destroyed in demoulding.
For this purpose the pattern plate is provided with an ejection plate which aids in compacting the sand in the deep holes of the pattern plate and aids in ejection and separation of the mote from said pattern plate.
Mote moulding machines for casting are generally provided with a chamber of rectangular cross section closed on one end by a movable wall, which may swivel to allow exit of the moulded mote, while the other end is closed by a plate associated to the plate for compacting and later ejecting the mote. The remaining walls of the moulding chamber are generally fixed, although PCT ES/99/00320 describes a moulding chamber of adjustable volume in which the lateral walls are mobile.
In these mote moulding machines, whether of fixed or variable volume, the plate connected to the compacting rammer is attached to the pattern plate. When the pattern plate has deep holes, corresponding to the identically shaped protrusions in the mote obtained, compacting the sand in these holes usually entails problems, to which must be added the risk of damage or wear of said protrusions when demoulding, that is, when separating the mote from the pattern plate.
The above problem is such that un many cases cores are required to obtain the Protrusions in the mote, which assemble the mote xe2x80x9ca posteriorixe2x80x9d entailing two additional operations: obtaining the core itself and attaching it to the mote.
The improvements disclosed by the invention solve the above described problem in a fully satisfactory manner.
To this end the improvements comprise including in the pattern plate an ejection plate which is placed between said pattern plate and the plate connected to the rammer which compacts and later ejects the mote.
The ejection plate is provided with hold down plates matching the deep holes of the pattern plate, in which the sand to be compacted must enter. Additionally, the ejection plate is provided with guide elements which prevent it from pitching.
Additionally, the pattern plate itself is provided with stops which allow the ejection plate to perform a compacting stroke before ejecting the mote.
As mentioned before, once the sand is compacted, including that contained in the holes of the pattern plate, the mote is ejected. Such ejection is performed by means of pneumatic pushers mounted on the compacting rammer and parallel to its shaft. Said pneumatic pushers act against the ejection plate and the latter, aided by the hold down plates opposite the holes of the pattern plate and of its stops, initiates the aforementioned compacting and ejection strokes.
Resetting of the system, i.e. recovery of the pattern plate stops and of the ejection plate itself is achieved by springs.